Monthly Archives: October 2014

Today is Physiology Friday so we thought we would share some interesting physiological facts.

The average human adult will breathe ten thousand litres of air in and out of their lungs every day – about the same as 37 bathtubs. 500 litres of this is carbon dioxide, produced by your body as a waste product. Your body uses about the same amount of oxygen.

There is a small amount of water in the air you breathe out. Over a day, this adds up to about 250 millilitres – the size of a teacup.

Horses can only breathe through their noses, not through their mouths. When a horse exercises, the air tubes in its nose can get bigger to allow more air in and out. Humans can breathe through their mouth or nose, so when we exercise we tend to breathe through our mouth.

There are about 480 million air sacs – called alveoli – in the lungs of a human adult. This is the same as the number of people in the world who speak Spanish as their main language.

If you took a pair of human lungs and spread out them flat, they would cover a tennis court.

Did you know that your lungs are never completely empty, even if you breathe out as far as you possibly can?

This week is Biology Week, ending on Friday with Physiology Friday! There are lots of events happening in schools, universities and public places around the country to demonstrate how the body works and to show off the research that physiologists do. You can look on the Physiological Society website to find out about some of these events.

As part of Biology Week, the Physiological Society are running a baking competition, asking people to create cakes and biscuits that show something about how the body works. If you’re on Twitter, search for the hashtag #BioBakes and see the creations – some of them are amazing! Vicky has entered the competition with this “Lung Cake”. What do you think? Let us know by leaving a comment!